(1) Field of the Invention
The present invention relates to an improvement in a package for containing a semiconductor element.
(2) Description of the Related Art
A conventional package for containing a semiconductor element, especially a glass-sealed semiconductor container package sealed by fusion bonding of a glass, comprises an insulating vessel having in the interior thereof a space for containing a semiconductor element, which comprises an insulating vessel and a lid member, and an external lead terminal for electrically connecting the semiconductor element contained in the vessel to an external electric circuit. In this package, a sealing glass material member is attached to each of confronting main surfaces of the insulating substrate and lid member, the external lead terminal is fixed to the main surface of the insulating substrate, respective electrodes of the semiconductor element are wire-bonded and connected to the external lead terminal, and the glass material members fusion-bonded to the insulating substrate and lid member are melted and integrated to seal the semiconductor element in the interior air-tightly.
In the conventional glass-sealed semiconductor element container package, the external lead terminal is composed of an electroconductive material such as Koval (an alloy comprising 29% by weight of Ni, 16% by weight of Co and 55% by weight of Fe) or 42 Alloy (an alloy comprising 42% by weight of Ni and 58% by weight of Fe), but since Koval or 42 Alloy has a high permeability, Koval or 42 Alloy has a defect as described below.
Namely, Koval or 42 Alloy consists solely of ferromagnetic metals such as iron (Fe), nickel (Ni) and cobalt (Co), and the permeability is as high as 250 to 700 (CGS). Accordingly, if an electric current flows in the external lead terminal composed of Koval or 42 Alloy, a large self-inductance proportional to the permeability is generated in the external terminal and this large self-inductance induces a counter electromotive force as a noise, and this noise is put into he semiconductor element to cause the semiconductor element to make a malfunction.